Gear cutter



Sept. 12, v J F LEAHY I GEAR CUTTER Original Filed July 11, 1928 2 Sheets-Sheet l Sept. 12, 1933. J. F. LEAHY 1,926,645

7 GEAR CUTTER Original Filed July 11, 1928 2 Sheets-Shet 2 nmmllllml,

Patented Sept. 12, 1933 i. j i f 1,926,645 I one CUTTER v o 1 "James FfLe'ahy; 'BuffaloQN." YQ, asisignor to" Far-; I I v relfBirmingh'aniCompany, l nc.;"'Buff'alo, Y.

(Application :July? 11, 1928.}; SeriaPNo. 291,830, V :Rene'wedAugus't 26,1932 i This inventionrelates-to-involute gear-tooth V generating machinesi using" a mast'erpinion eut- V *ter, -and"more partieularlytoaan 1 improvement in -111 this'type of'machine. "Theci-ztters of-this invention are-inth form bf a -pinion gear, -the contours ofthe teeth ,upon theper-iphery thereof being-accurately generated No." 1 868345 issued to W'illi'am Y E. Sykes and *datd MayfEl-st, 1928. Such cuttersjflikef all cutting' toolsysuchasmilling cutters; hobs'and shaper =tools;-and-especially relatively large ones are 7 expensive to ma-kedue to the'care required-in ;"iorming'i -hardening-and grinding them." 'It -is esrn'enti to {insure that each cutting' edge will have "the same degreebfhar'dness and'temperfthe lack of whfch will result "in uneven w ear' {of the cut- :ting-dges imposing' a"doub1e"'burden-on some of *the teethyand causing inaccuracies-to appear in' the' shape of tthe article being cut. 1

"rhe material amnion these cuttersare r'nade -*is "expensiveand "errors during the making, "breakage," or faults developingf'duringfthejuse th'erebf usually require-that the entire cutter "be "replaced-by'anew 'one. 'The operator using such cutters and appreciating ftheir valuefmany times underestimates their-strength and being unneces- 'sarily; cautious retards "the "speeds and-feeds of the machine'inwhich they are used, which lowers the production thereof andincreases the cost of "the" article-being produced.

"expensive to "manufacture and low in cost of I Another object of this inventionis to provide a gear-cutter or the pinion type "of such structure that the "cutting edges; may be thoroughly and uniformly hardeneda id tempered. j Still andtherfiobje'ct'of thisinventionxis toprovideanflrnproved' gear cutter of this type, which wi11beeconomical to make because of, its 'struc- One of the objects of this ih'ventionisto protion;

' -"vide" an-"improveclgear" cutter-of the pinion type. V, *Andther' object" of this invention is to 5 pro- 'vide a gearcutter whichwill be relatively inp i I "Fig'; 12-is an end face view'ofapa'rt of a cutter 0 videa cutter for gear cuttin'g'or the likm-by the use ofwhich theteeth of gears-may be cutaand j accurately formed at relatively higher "speeds --than'-'has heretofore abeen. practieableg."

partand cutting parts, the-former being adapted v to -rem'ovabl y receive and firmly support the latter; V *byg rindingthesame after-hardening. PA cutter of this type is shown and described in Patent- A1 still further *obie'c t ofth-is invention is to providein a gear cutter of thepinion type-abody "pait having cuttingpa1ts' 'removably{Supported thereby, and ineans {to rigidlyandfindividually secure-saidcutting partsto the 'body partg I To these and other ends, the invention consists in the novel'features'andcombinationsof parts to r V V ,behereinafterdescribedand claimed. 'peeially diflicult,'--'even with; the hestofyequip- I :the accompanying drawings:

mechanism for operating a gear -'cuttererhbo'dye ing the features "of 'this invention; r I {Fig 2 is-a partial' front end viewfof apinion type gear cutter, embodying the features-of this invention 1 i Fig: 3 is a partial face view of the cutter "shown inFig,1; 1 V Fig- 1 isa-sec'tion on line i i-ofFigjzi-* 1 Fig; 5' is-a"se'ction on line- 5-5 ofFigi 2 Fig. 6 is a section on line-6;-;-6of FigF3;' Figf'flf illustrates? a-slight' modification -in the ate asomewhat 'different form of gear cutter; Fig. 8 is a partial frontend View fofa pinion," type ge'ar cu'tter 'of somewhat different forrm but whichalso embodies the-ieaturesof this' inven- I Fig-11 is-a-sectionsimilar to'Fig.'10,;butof 7 somewhat modified,form'of'cutten-and shownin Fig. 8.

K The fmechanisms diagrammatically shown dn Figs. l and 7 i llustratethe'general arrangement of the cutter "control and operating parts of a machine capable of cutting-teeth in the 'fac'esbf gear" blanksby the principle: of ,gearcutting known as involute gear'genera'tionyby means-of a 'masterIpinion' cutterj -A"de'tailed description of theistructurapperation andmethod of-eutting gears-by thisprinci'ple maybe-had-by reference -to"the" copen'cling applications of william Sykes, Serial "Nos: 641,126-and 164,825 'fi1ed-1-espectiv'ely May 24, I923and January 31J1'927,

which have-matured intofP'atent's' No. 1,750,030 and No. 1 ,314,348 respectively.

Briefly, the action of the mechanism illustrated in Fig. 1, upon the cutters, is. one wherein a combination of movements is provided. The

carriage 10, slidably mounted. iii-suitable ways in a frame 11, is reciprocable therein by means of a crank 12. Cutter spindle supports 13 and 14 carried upon and ,reciprocable with the carriage 10, support respectively cutter spindles 15 and 16. Cutters 1'7 and 18 are secured respectively to the spindles 15 and 16;: The spindles 15 and 16 and the cutters thereon reciprocate with the supports 13 and 14 and are also rotatablerelatively thereto, the spindles being rotatably mounted in bearings in their respective supports. Each spindle is slidably mounted within the sleeve-like hub of a wormwheel' while being con nected thereto for rotation therewith, thus spin 7 dle 15 may slide through and be rotated by worm wheel 19, and spindle 16 may slide through and be rotated by worm wheel 20.v The worm wheels 19 and 20 are driven by worms 21 and 22, respectively.

The connection between the spindles 15 and 16in Fig. 1, and the worm wheels, comprises the nuts 23-and 24,]secured uponthe interior of the sleeve-like hubsofthe respective ,worm wheels,

and: cooperating guide members 25 and 26 secured to spindles 15 and 16 respectively. The

guide members 25 and 26 are engagedby the nuts 23 and 24 respectively, and due to the helical form of the; engaging surfaces of these parts ,operate to twist the spindles and cutters during the reciprocation thereof,-. as 'wellas to cause rotation of the same'when the respectivewor-m wheels 19 and ,20 are rotated.

7 During these operationathe teeth of a herringbone or doublehelical gear 27 will be generated and cut by the cutters 17and'13. It will be un derstood thatthe reciprocating movement forces the cutters across the blank in the material thereof, that thecontinuous rotation of the cutters by means of theyvorm wheels causes them to rotate with the gear blank, which is rotated in synchronism therewith, whereby a true involute form of tooth is generated, and that the twist caused by-thef action of the guides and nuts during reciprocation controls the helical angle of the gear teeth being out. i s

In Fig. '7, thenuts 239 and 24 and guide members 25 and 26 do not require helical engaging surfaces, inasmuch as no twisting of the cutters is required, since lspur gears having straight teeth are adapted to be cut by this mechanism. The spindles 15 and 16 and. the cutters secured thereto, of this mechanism, therefore reciprooate in a straight path while being rotated by theworm wheels 19 and 2og respectively.

7 Q Thedouble helical'gear cutters 1-7'and 18, as

form involute gear teeth in the gear-blank being of being forced into the; material of'the gear well as the spur gear cutter 23 must have their I cutting edges of true form in order to correctly cut, and be capable of withstanding the strains blank at relatively fast speeds andfeeds, in order to completely 1 form the gear in a minimum amount of time, so that the production cost of the'gear will not be prohibitively high. 7

. .To further increase the efliciency of this type of machine, the cutters should be capable of substantially continuous service, so that interruptions due to cutter breakage. willnot result in a serious loss of time. The teeth of the cutters should, therefore, be capableofbeing thoroughly and evenly hardened and, tempered. To obtain these advantageous; results, cutters 17, 18 and 28v may be made according to the structures shown in the drawings. Fig. 2 shows a portion of one of a pair of cutters adapted to out double helical teeth, and when used with a mechanism such as shown in Fig. 1, this particu- -lar cutterwould be secured to spindle 16 and be the cuttershown at 18.. This cutter hasa disklike body portion 30, provided with a .central spindle opening 31, and teeth 32 formed upon its-periphery. The teeth 32are cast or otherwise formed integral with the body portion 30 and "are slightly reduced in dimensions such as width and height from those dimensionswhich would :be required if theseteeth were to act as the cutting means for the cutter. The body portion 30 and the teeth 32 thereon are preferably made from a steel casting or forging, which characteristically is tough and rugged, though easily workedinto form by tools. One end face of each tooth 32 is out back to form an outwardly dione at the base of each tooth,- and a series of forwardly facing ,endfa ces 34 disposed on the teeth and spaced rearwardly from the, front end face of the body portion 30. The cutter 1'7 is. provided with these same features, anddiffers only from cutterlS inthat the teeth 32 of cutter "17 are disposed at the left hand spiral anglewhile teeth 32 of cutter 18 are ata angle.

A cuttingblade .or plate 35 disposedupon the end face of ,eachtooth 32, withits base 36 right. hand spiral resting uponthe shoulder 33-and its rear end surface 37 abutting the end face34-of each tooth.

Theblades 36 are secured ,adjacent-theend face of each tooth 32, by means of bolts 38 and39,

the heads 40 of which are sunk into counter bores 41 in'the frontface of the blades 35 an'd the nuts .42 'o f which lie-in counterbores 4 3, provided in the rear face of the teeth 32., ,Each blade 35 is peripherally extended at its baseand at each side thereof beyond the edge of its. sides 4e and rectedseries of shoulders 33, which are disposed 45 to provide clampinglugs 46 and 4 7., A wedge ,48 having a threaded studi49 secured thereto is disposedbetweeneach plate 35 and engages the 'side lugs of adjacent blades, and by means of a nut 50 threading1y engaged .to the stud49 is forced radially inwardly with respect to the center of the cutter to clamp the blades againstthe shoulders. 33, and to support them peripherally.- The nuts 50 are disposed in a recess formed in the face of the body portion, through the} wall of and into which the studs 49 project.

The platesor blades 35 are substantially identical in form and size and arepreferably made of]relativelyexpensive high speed steel. Being substantially identical and comparatively small replaced by a newone or repaired without 'disturbing the others'or' affecting the body portion 30 in any manner.

I Fig. 8.jshows a portion of a cutter 23 for use in cutting the teeth of spur gears, adapted to be secured to either spindle 15 01'16 of the mechanism shown in Fig'. 7; fIhe body parted of this cutter is similar to the body part 30, in that it is preferably formed from the same, kind of izmaterialywand serves :the' same:

general. purpose. .1 its .astructure isfisomewhat. 1 diiferentiin that .the

vtishou'lderszat atherbasessofithe teethform in con- :junctioman outwardlytan'd radially: directedan- .aznularwshoulder 151,-:gand a forwardly facing shoulden 52; both of. which "extend continuouslyi. about lithe; body:part 5.0;.theashbuldei: l. beingilconcen- :tric:towtheibodygpartl.

.1 (A1. plurality of f substantially? similar cutting blades :orplates" 53rrcorresponding in .:number to the number of teeth? 5 i uformed' iupon Ithewbody 1 ;-part'*5 0, arespacedeaboutuandyseatauponuthe shoulderi 51 the; base" portiorrx55s of: cache blade being formed to fitthe curve thereof; The blades 53-areieach securediin abutting relation against the end face 56 of the tooth 54, and the forwardly facing shoulder 52, by means of bolts-157 and'58,: the heads of which are seatedin counterboresinthe plates 53. The shanks'of the bolts 57 and 58 pass axially through the teeth 54 and are threadingly engaged by nuts 59, whereby the blades 53 may be firmly clamped into place.

tions 36 and of the plates 35 and 53 res'pec-' The teeth 32 and,54 of the body portions 30 and 50 respectively, serve as backing members for the cutting blades 35 and 53, abutting asthey do substantially the entirearea of the rearface thereof; Y To insure that the cutting plates 53 will not slip or give sideways, atongue and groove connection may be made between the rearface of each of the blades 53 and the'front face of each tooth 54, as shown at 60 in Figs. 9 and 10, or this feature may be omitted as shown in Fig. 11. Obviously this tongue and groove feature could be applied to the form of tooth shown in Figs. 2 to'6 inclusive. Wedges 61 are disposed between the blades 53 and are formedand act as do the wedges 48 previously described, each having a stud member 62 engaged by a nut 63. The.

Wedges/18 and 61 are preferably provided and used in the cutters in this invention, but by increasing the width peripherallyof the base pork tively, sothat they will eachengagethe adja cent one, the wedges might'be dispensed with.

' By using the improved and. novel structure above disclosed, a practical, ruggedpand accurately operating composite cutter is provided and heavier cuts in a gear blank may 'be taken, and

the machine employing them may be operated at higher speeds and feeds than has heretofore been possible when cutters madein one piece and known as solid cutters have been used. Less loss of time is experienced andthe operator is inspired with confidence in using these cutters, because even under excessivelyheavy cuts the destruction. or

} excessive damage toa relatively highly expensive tool is not possible, due to the structure-whereby should one of thecutting blades be damaged an-' other can readily be supplied, whereas in'the case of a solid cutter the entire tool must be replaced.

The individual blades of. the novel form of cutter of this invention cost but-a small fraction of the cost of an entire cutter of the other form; It is possible withthis form of cutter, whereina' iferred' embodiments: ofrmy invention, it iis. under-. be zlimited to, 'all' of 1the1de-Q Z stoodrthatziti'isanot to I, tails. shown, butfis" capable. ofrimodificationaatid variation: which will lie .within .theispiritt ofrthe :Whatrclaimlis: v f iIna-gear cutt'erof thetzpin'ion :type,'.a body having JJEBthILUPOn its. periphery; the end: vface 'of t vinventionrand. ewithincther LS'CODGSOfIthGZ appended a cache of-iys'aid teethcbeing: spaced tfromithe' side of. thez-bodyi to form an outwardly'idireeted :fixed a shoulder on the body at the base of thetooth,

:cutting blades in theiiform" 'ofrigear :teeth seated directly. 011 said shoulders, andv meansrfoniurgingszthet' cuttin'g'i blades radially inwardly against said shoulders.v r

,In a gear cutter of the piniontype, abody having teeth upon its periphery, the end face of each of said teeth being spaced from the side f the body to form an outwardly directed fixed shoulder on the body at'the base of the tooth,

cutting blades in the form of, gear teeth seateddirectly on said shoulders, and means between adjacent blades and engaging both thereof, for

spacing said cutting blades about said body and O urging the same radi shoulders. V I

3. In a gear cutter of the pinion type, a body having teeth upon its periphery, the end face ally; inwardly against said of each of said teeth beingspacedfrom the side fi r of the body to form an outwardly directed fixed shoulder on the'body at thebase of the, tooth, cutting blades in the form of gear teeth'seated directly on said shoulders, and'means for spacing said cutting blades about said body and urg g ing the same radially inwardly against said shoulders, said last named. means including a plurality of'wedges mounted between the cutting blades, the latter being provided with tangentially directed side edg wedges bear.

4. A composite gear cutter of the pinion type comprisinga body having teeth upon its periphery and underlying fixed shoulders having out-f wardly directed faceslocated adjacent the end faces of said teeth, cutting blades having their inner edges seated upon said shoulders and exe faces against which the l tendingalongside the end faces of said teeth,

eachblade having holes extending completely therethrough at different'distances from the cen- M25 terof the body and the corresponding tooth having holes-that register with those of the blade,

the holes inthe blade being. counterbored at-the frontface of the blade, and fastening; bolts pass- ;v ingthrough the registering holes in each blade and tooth and, having their ends disposed in the counterbores at the front .face ofv the blade, said bolts beingadapted to draw said blades in a direction generally lengthwise of the teeth against e the end'faces of the teeth and to prevent move-" ment-of the blades relatively to the teeth.

5. A composite gear cutter. of the pinion type ery, the end faces" of said teeth at" one sideof thecutter beingso located that there is presented an outwardly directed fixed shoulder at the base ofeach tooth, cuttingblades lying, against the end faces of saidteethand-"seated at their inher edges upon the outer faces of saidshoulders, each blade having at a point spaced outwardly from the shoulder a hole extending through the blade from front to rear and the tooth having a through front-to tering with that ofthe blade, the hole in' the blade being counterbored at' the front face of comprising abody having teeth upon its 'periphcorresponding -re'arhole regis- I use bore at the frontface of the blade and a .nut at-the rear face of the tooth, said bolt exerting pressure on the blade in a direction generally lengthwise of the tooth to clampit against the end faceof the tooth, and va second bolt spaced outwardly from thefirst and likewise passing through-a front-to-rear hole in theitoothand engaging theblade at. its outer part forfsecurthe blade, a fastening bolt for theblade passing through the registering holes in the bladeand tooth and having ahead, within the counteroutwardly directed faces located adjacent the end faces of said teeth, said outwardly directed faces being substantially parallel to the cutter axis,

cutting blades having their inner edges seated upon said shoulders and extending alongside the endcfa'ces of said. teeth, and means for securing eaehcutting blade in position comprising a bolt extending. through the corresponding tooth and engaging the cutting, blade to draw it against the end face of the tooth, said bolt being located adjacent the base of the blade, and a second bolt 7 spaced outwardly from the first and acting on the blade to draw the blade in substantially the same direction. v Y

JAM S" F. EAH'Yf 

